Comments on: Are they identical? On twins and twin celebrities

By: Hazel

Hazel — Wed, 06 Aug 2008 16:44:08 +0000

This is just a quick but true antidote about the on going question “Are they twins?”
I have younger brothers who are twins. One time years ago when our parents took all of us shopping a lady came up to us and asked my dad if my brothers were twins. Now, my dad,tired of being asked this question said “No ma’am, they are brothers.” We all still have a good laugh about this incident.

By: Science-mom

Science-mom — Mon, 28 Jan 2008 22:13:04 +0000

Thanks for this interesting comment. I stand corrected and I`m simply grateful that my identical twins turned out to be real boys.

By: ana

ana — Sat, 19 Jan 2008 05:02:14 +0000

Actually you are incorrect.

Until very recently, in fact, experts thought monozygotic/identical twins had to be same-sex. But now we know that there are certain rare instances when monozygotic/identical twins can actually be different-sex individuals; when this has occurred and been documented, the twins are genetically identical in every way other than a slight chromosomal difference.

The rare instance in which a set of boy/girl monozygotic/identical twins occurs is the result of Turner’s Syndrome, in which both individuals are actually XY boys, but one child loses the Y chromosome, yielding a baby who is XO. One twin appears externally to be a girl, but grows up infertile, short, and usually with a couple of other recognizable physical characteristics. Miscarriages occur frequently in such pregnancies, which is why these sets of twins are rare.

http://www.twinsmagazine.com/facts.html